Conventionally, liquid crystal display apparatuses have been widely used as various display means, such as televisions, PC monitors, cellular phones, tablet PCs, portable game machines, or in-vehicle monitors. In recent years, from the viewpoints of finer pitches, weight reduction and slimming down, and the like, into such liquid crystal display apparatuses, there have been employed what is called COG (chip on glass), the direct mounting of an IC for liquid crystal driving on a substrate of a liquid crystal display panel, and what is called FOG (film on glass), the direct mounting of a flexible substrate having a liquid crystal driving circuit formed therein on a substrate of a liquid crystal display panel.
For example, as illustrated in FIG. 10, a liquid crystal display apparatus 100 into which the COG mounting is adopted has a liquid crystal display panel 104 performing a main function for liquid crystal display, and this liquid crystal display panel 104 has two transparent substrates 102, 103 made of a glass substrate or the like and facing each other. Furthermore, in the liquid crystal display panel 104, these transparent substrates 102, 103 are stuck to each other via a frame seal 105, and provided is a panel display unit 107 in which liquid crystal 106 is sealed in a space surrounded with both of the transparent substrates 102, 103 and the seal 105.
On the internal surfaces of the transparent substrates 102, 103 facing each other, a pair of transparent electrodes 108, 109 made of ITO (indium tin oxide) or the like, having a stripe form are formed respectively in such a way as to intersect each other. Furthermore, both of the transparent substrates 102, 103 are configured to have a picture element as a minimum unit of liquid crystal display to be formed by the intersection portion of these transparent electrodes 108, 109.
Of the transparent substrates 102, 103, the one transparent substrate 103 is formed to have a larger plane size than the other transparent substrate 102, and, an edge portion 103a of the transparent substrate 103 thus formed larger is formed with a terminal portion 109a of the transparent electrode 109. In addition, on the transparent electrodes 108, 109, orientated films 111, 112 each undergoing a predetermined rubbing process are formed respectively, and the orientated films 111, 112 allow the initial orientation of liquid crystal molecules to be controlled. Furthermore, a pair of polarizing plates 118, 119 are provided on the outside of the transparent substrates 108, 109, respectively, and these polarizing plates 118, 119 is configured to allow the vibration direction of transmitted light from a light source 120 such as a backlight to be controlled.
On a terminal portion 109a, an IC for liquid crystal driving 115 is thermocompression-bonded via an anisotropic conductive film 114. The anisotropic conductive film 114 is obtained by mixing conductive particles into a thermosetting type binder resin and making the mixture into a film, and the thermocompression bonding of the anisotropic conductive film 114 between the two conductors allows electrical continuity between the conductors to be secured by the conductive particles, and mechanical connection between the conductors to be maintained by the binder resin. The IC for liquid crystal driving 115 is configured such that selective application of a liquid crystal driving voltage to the picture elements causes the orientation of liquid crystal to be partially changed, thereby allowing predetermined liquid crystal display to be achieved. It should be noted that, as an adhesive constituting the anisotropic conductive film 114, the most reliable thermosetting adhesive has been commonly used.
In the case where the IC for liquid crystal driving 115 is connected to the terminal portion 109a via such anisotropic conductive film 114, first, the anisotropic conductive film 114 is temporarily compression-bonded on the terminal portion 109a of the transparent electrode 109 by a not-illustrated temporary compression bonding means. Subsequently, the IC for liquid crystal driving 115 is disposed on the anisotropic conductive film 114, and then, as illustrated in FIG. 11, the thermocompression-bonding means 121 is made to generate heat, while the IC for liquid crystal driving 115 is pressed together with the anisotropic conductive film 114 toward the side of the terminal portion 109a by a thermocompression-bonding means 121 such as a thermocompression-bonding head. The heat generation by the thermocompression-bonding means 121 causes a thermosetting reaction of the anisotropic conductive film 114, whereby the IC for liquid crystal driving 115 is adhered onto the terminal portion 109a via the anisotropic conductive film 114.